Conventionally, many semiconductor integrated circuit devices (hereinafter “ICs (integrated circuits)”) such as power supplies or motor drive units that drive a power transistor are provided with a temperature protection circuit (a so-called thermal shutdown circuit) as means adapted to prevent breakage of the IC (especially breakage of the power transistor that generates heat) due to abnormal generation of heat (see, for example, Patent Publications 1 and 2 filed by the applicant of the present application).
As other conventional arts related to the present invention, there have been disclosed and proposed: a temperature protection device in which a plurality of power elements are each individually checked for abnormal generation of heat, and a power element that is found to be abnormally generating heat is made to stop its operation and threshold temperatures of the other power elements, which may be effected by the abnormal generation of heat, are temporarily raised, thereby preventing normally operating power elements from being stopped (see Patent Publication 3); and an abnormal temperature detecting circuit that is capable of outputting an abnormal-temperature signal having high detection accuracy by increasing the output difference between a temperature detecting circuit and a temperature setting circuit at temperatures other than a set temperature by use of temperature-dependent difference in output variation coefficient between the temperature detection circuit and the temperature setting circuit (see Patent Publication 4).